In recent years, there have been developed soft bag preparations obtained by diluting injectable drugs into intravenous drip preparations beforehand and filling them in containers having flexibility such as plastic-made containers. These soft bag preparations are considered to be useful for their superior disposability to glass-made bottles and ampoules in addition to their convenience and readiness at the time of use.
However, drugs led by nitroglycerin, preparations containing proteins such as albumin and hormones, hyaluronic acid drugs, vitamins, trace elements, insulin, anticancer drugs, antibody drugs, radical scavenger drugs and the like are known that their active ingredients adsorb on or permeate through the base materials of medicine containers, such as conventional polyolefin-based resins (PO resins), e.g., polyethylene (PE) and polypropylene (PP), and polyvinyl chloride, and therefore involve such problems that the active ingredients in content fluids may decrease and interactions may occur between additives or low-molecular components contained in the base materials and the active ingredients in the content fluids.
In regard to these problems, it has been proposed, for example, in Japanese Patent No. 3227709 (Patent Document 1) and JP-A 2004-298220 (Patent Document 2) to use cyclic polyolefin resins (COP resins) in container main bodies as resins that are free of adsorption or permeation of active ingredients.
In JP-A 2008-18063 (Patent Document 3) and JP-A 2005-254508 (Patent Document 4), packaging bags formed of laminated films having COP resins in innermost layers thereof are disclosed.
These packaging bags are described to allow retort sterilization treatment and to inhibit the adsorption of ingredients, and hence, to be suited for use with injectable preparations the active ingredients of which are prone to adsorption.
In the above-cited Patent Document 3, it is also described to the effect that the innermost layer of a container film may be formed of COP resin and a port formed of COP resin may also be used as an outlet port. As methods for welding together a port portion and a plug portion that serves to hold a rubber plug in place, heat sealing and ultrasonic welding are also described. However, no indication is made at all about the problematic occurrence of crazes upon ultrasonic welding. Moreover, no consideration is made either for the prevention of the occurrence of cracks when a container with a content fluid filled therein is accidentally dropped.
The above-cited Patent Document 4 also contains a description of a medical container which uses COP resin in its innermost layer. It is also described that, from the viewpoint of imparting flexibility to an outlet port to make an improvement in the sealing performance with a sheet, a thermoplastic elastomer may be blended at a blend ratio of not greater than 20%. In other words, it is disclosed to blend a thermoplastic elastomer in a port portion of the outlet port, said port portion being the part where the outlet port is welded with a sealant of the container. However, absolutely no detailed disclosure is made about a plug portion that serves to hold a rubber plug in place. It is disclosed that, if the thermoplastic elastomer in the port portion exceeds 20%, there is a greater potential problem of adsorption of the ingredient of a content fluid on the port portion or the container may be provided with inferior retort sterilizability.
Now assume that a port portion, which makes up an outlet port, and a plug portion, which serves to hold a rubber plug in place, are both formed of COP resin. Compared with low-density polyethylene or the like, COP resin has a greater molecular weight, is more linear, and owing to cyclic hydrocarbon groups, has a bulky molecular structure in its molecular skeleton. Therefore, the thermal motion of its molecular backbone is restricted, and parts, which are both formed of COP resin can hardly be welded together by conventional heat sealing. In contrast, these parts can be welded together by ultrasonic welding as COP resin is hard. Ultrasonic welding of COP resin can be achieved in a short time, and is effective and preferable as a welding method. However, COP resin is brittle so that compared with other resins, a COP resin layer is more prone to occur crazes or dusting by ultrasonic waves. There is, accordingly, a potential problem that a fluid leak may take place through the crazes or foreign matter may enter a content fluid as a result of dusting.
A container, for example, with an infusion fluid filled therein is generally hung to perform its administration by drip infusion. There is, however, a potential problem that upon hanging the container, it may be accidentally dropped. In the event of dropping, there is high possibility that a plug portion of an outlet port, said plug portion being arranged at a position opposite to a hanging hole, may first come into contact against the floor. Moreover, COP resin is hard and brittle, and therefore, is prone to fracture. Accordingly, there is a long-standing desire for the development of a medical fluid container provided with an outlet port that is free of adsorption or permeation of an active ingredient, can prevent the occurrence of crazes or dusting upon welding of the outlet port, and is resistant to fracture even when an impact is applied as a result of dropping or the like.